盐藻胞浆hsp70 cDNA的克隆及其mRNA的诱导表达

用cDNA末端快速扩增方法克隆得到了一个2652bp的盐藻(Dunaliella salina)胞浆hsp70 cDNA全长，编码着650个氨基酸残基的多肽。推导的氨基酸序列有2个ATP酶结合位点和一个多肽结合区。由克隆得到的盐藻cDNA推导的氨基酸序列，经GenBank blast后与数据库中胞浆hsp70序列一致。与莱茵衣藻(Chlamydomonas reinhardtii)、人、小麦(Triticum astivum)和啤酒酵母(Saccharamyces．cerevisiae)胞浆hsp70的序列一致性分剂为83％、80％、81．5％和80．5％。Northern印迹显示，90min后，mRNA量在40℃热休克时是光诱导时的3倍。光诱导则使hsp70 mRNA积累相对迟缓。结果表明，所克隆得到的hsp70基因蛋白产物定位在盐藻细胞浆中，光诱导和热休克均可以使hsp70 mRNA水平明显增高，但以热休克为显著。     

盐湖生物学研究进展——第二届"盐湖生物学及嗜盐生物与油气生成学术研讨会"综述

盐湖生物学是研究盐湖水体及其沿岸环境中生命现象和生命过程规律的科学.为进一步促进我国盐湖生物学研究,第二届"盐湖生物学及嗜盐生物与油气生成学术研讨会"于2007年9月在京召开.会议主要取得如下成果:(1)在"大盐湖产业"体系基础上,提出了"盐体系"研究模式,初步归纳了盐体系研究与生物学交叉的几个主题,为开展盐湖生物学研究提供了理论指导.(2)盐湖生物提供基因资源和新生物技术:极端嗜盐古菌蕴藏着丰富的可开发资源,是真核生物遗传过程研究得天独厚的原核模型.(3)对盐湖生物在油气生成中的作用有了新的认识,89%的已探明的原油和80%的天然气产出于含盐盆地;盐湖相可以发育为优质烃源岩,已发现盐湖相烃源岩形成的大规模油气资源.     

DYNAMIC STUDIES ON FLAGELLAR REGENERATION IN DUNALIELLA SALINA

INTRODUCTIONMicroalgalbiotechnologyhasattractedmoreandmoretheinterestofscientistsandpeopleex ploitingitscommercialpossibilitiesasitisthebiotechnologythatcanmatchbacterialbiotechnologyinthecomingcenturyintheaspectofeconomicreturnoninvestment.Dunaliellasalinaisoneofthemostdetailedlystudiedunicellulargreenalgae,hassomeuniquescientificvalues,andgreatestpotentialformasscultureasafoodsource ,andisrichestalgalsourceofglycerolandβ carotene(Borowitaka,1 988;Ginzburg,1 987) .Optimizingperformanceo…     

Dynamic studies on flagellar regeneration inDunaliella salina

Flagella, the basic locomotive organ in algae, as well as bacteria and some cells of animals or high plants, would be damaged in the well stirred mass culture due to the strong forces caused by the fast mixing impellers. The dynamic regeneration of the flagella in deflagellatedDunaliella salina was studied microscopically by using a bench-top flat-bottom photobioreactor. The results showed that 90 minutes was necessary for the repair of flagella, after which half of the cells became motile as their flagella generated within 120 minutes and nearly all of the cells could swim freely within 180 minutes. Contribution No. 3503 from the Institute of Oceanology, Chinese Academy of Sciences.     

重金属胁迫对杜氏盐藻生长及叶绿素荧光特性的影响

研究了杜氏盐藻Dunaliella salina在不同浓度的Cu2+、Zn2+、Cd2+等重金属离子胁迫一段时间(24、48、72和96 h)后,叶绿素荧光特性的变化情况。测定的主要参数有:PSII的最大光能转化效率(Fv/Fm)、PSII的潜在活性(Fv/Fo)、PSII的实际光能转化效率(Yield)、相对光合电子传递效率(rETR)、光化学淬灭(qP)和非光化学淬灭(NPQ)。研究结果表明,当Cu2+浓度范围在600~800μmol/L时,杜氏盐藻的Fv/Fm、Fv/Fo、Yield、rETR和qP均明显降低,NPQ变化不规律,随着胁迫时间的延长,除qP在96 h时有所上升外,各荧光参数均逐渐降低;Zn2+胁迫下Fv/Fm、Fv/Fo、Yield和rETR随着浓度的增加而降低,NPQ先下降后上升,qP仅在Zn2+浓度范围(800~3200μmol/L)下明显下降,随着胁迫时间的延长,各荧光参数均逐渐降低;Cd2+胁迫下各荧光参数均明显下降,随着胁迫时间的延长,Fv/Fm、Fv/Fo和NPQ先下降后上升,在48 h时达到最低值,Yield、rETR和qP均逐渐降低。在3种重金属离子胁迫下,细胞密度和叶绿素相对含量也显著降低。根据3种重金属离子的半抑制浓度(EC50),其毒性大小顺序为Cu2+Cd2+Zn2+。     

Uptake and metabolism of arsenate by anexic cultures of the microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum

Axenic cultures of the microalgae species, Dunaliella tertiolecta and Phaeodactylum tricornutum were grown at arsenic (As) concentrations typically found in uncontaminated marine environments ( 2 µg L^− 1) under different phosphorus concentrations. D. tertiolecta accumulated higher arsenic concentrations (mean: 13.7 ± 0.7 µg g^− 1 dry mass) than P. tricornutum (mean: 1.9 ± 0.2 µg g−1 dry mass). Media phosphorus concentrations (0.6–3 mg/L) had little influence on microalgae growth rates or arsenic accumulation. Arsenic was present as lipid bound (29–38%; 4.2–9.5%), water-soluble (20–29%; 26–34%) and residue bound (41–45%; 57–69%) arsenic species in D. tertiolecta and P. tricornutum respectively. Hydrolysed lipids contained mostly glycerol arsenoribose (OH- ribose), dimethylarsinate (DMA) and inorganic arsenic (As(V)) moieties. Water-soluble species of microalgae were very different. D. tertiolecta contained inorganic arsenic (54–86%) with variable amounts of DMA (7.4–20%), arsenoriboses (5–25%) and traces of methylarsonate (MA) ( 1%). P. tricornutum contained mostly DMA (32–56%) and phosphate arsenoribose (PO₄-ribose, 23–49%) and small amounts of OH-ribose (3.8–6.5%) and As(V) (9–16%). Both microalgae contained an unknown cationic arsenic species. The residue fractions of both microalgae contained predominately inorganic arsenic (99–100%). These results show that at natural seawater arsenic concentrations, both algae take up substantial amounts of inorganic arsenic that is complexed with structural elements or sequestered in vacuoles as stable complexes. A significant portion is also incorporated into lipids. Arsenic is metabolised to simple methylated species and arsenoriboses.     

氮磷比对盐藻生长及甘油和色素累积的影响

将盐藻在［Ｎ］／［Ｐ］（氮磷浓度比）为０．５至６０．０的培养液中进行培养,测定了不同实验条件下［Ｎ］／［Ｐ］比值对盐藻生长、培养液中甘油和叶绿素含量以及β－胡萝卜素累积的影响,并初步建立了盐藻在不同［Ｎ］／［Ｐ］比值下的生长动力学模式。研究结果表明,在［Ｎ］／［Ｐ］为２５时,盐藻的生长最佳。［Ｎ］／［Ｐ］比值变化对甘油含量的影响不大。［Ｎ］／［Ｐ］比值小于１５时,叶绿素含量随［Ｎ］／［Ｐ］比值的增加而增加;比值大于１５时,叶绿素含量基本不受［Ｎ］／［Ｐ］比值变化的影响．单细胞β－胡萝卜素含量随［Ｎ］／［Ｐ］比值的增加而减少,而培养液中β－胡萝卜素含量在［Ｎ］／［Ｐ］比值小于１５时基本不受影响,比值大于１５时含量呈下降趋势。     

海水小球藻脂肪酸组成研究

“Ｍａｒｉｎｅ’,Ｃｈｌｏｒｅｌｌａ,俗称海水小球藻,是水产养殖中一种常用的饵料微藻。其细胞较小,呈卵形或圆形,在形态上与绿藻纲小球藻属中的许多种类极为相似,因而人们常把它与绿藻纲的小球藻混为一谈。为了澄清人们长期以来对海水小球藻的模糊认识,本文对海水小球藻的脂肪酸组成进行了研究,并与盐生杜氏藻（Ｄｕｎａｌｉｅｌｌａ　ｓａｌｉｎａ）及一种微绿藻Ｎａｎｎｏｃｈｌｏｒｏｐｓｉｓ　ｏｃ－ｕｌａｔａ的脂肪酸组成进行了比较,以明确海水小球藻的分类地位。１材料和方法１．１藻类的培养取刚扩大的海水小球藻和盐生…     

磁性微球吸附法研究盐藻细胞的疏水性

采用正相悬浮聚合法制备了聚苯乙烯－二乙烯苯磁性微球。由于微球表面的聚苯乙烯是疏水性材料，可用于制定微生物细胞表面的疏水性。用聚苯乙烯磁性微球吸附法测定了不同生长期盐藻细胞的表面疏水性，以及pH值、NaCl浓度、Fe^3 浓度、（NH4）2SO4浓度对盐藻细胞疏水性的影响。结果表明，盐藻细胞表面具有疏水性质， 其疏水性与细胞生长阶段及环境条件有关。     

耐低温杜氏藻突变株的诱变和鉴定

采用紫外线辐射的方法对巴氏杜氏藻(Dunaliella bardawil)进行诱变.经过低温(5±1℃)筛选,得到一耐低温的突变株,命名为Dunaliella bardawilvar.L-5 Zhou&Liu(简称L-5).研究表明,在5±1℃光照培养箱中光强1 100 lx培养57 d,L-5仍继续处于对数生长期,而对照组早已进入生长平衡期,此时L-5藻细胞密度为对照的2.59倍.蛋白质SDS-PAGE电泳表明,在大约36和158 kDa处L-5比对照各多出一条新的蛋白带,同时在大约27和29 kDa处L-5出现比对照高得多的两条蛋白表达带.RAPD分析表明两者的遗传相似系数为0.768.由此作者初步认为L-5确为一耐低温的杜氏藻突变株.